Submersible structure



May 4, 943 1'. G. MYERS 2,318,181

SUBMERSIBLE STRUCTURE Filed NOV. 8, 1957 5 Sheets-Sheet l Titl. E

Thomas ens 3%/ ATtRNEY sUBMERsIBLE STRUCTURE Filed Nov. 8, 1937 3Sheets-Sheet 2 20s uw 7 Y 2a rial- 4- im 206 Tap/2:50 v/// 215 2/5ATTORNEY May 4, 1943. T, Q MYERS 2,318,181

SUBMERSIBLE STRUCTURE Filed Nov. 8, 1957 3 Sheets-Sheet 5 Myers yBYThorn s ATTQR N EY Patented May 4, 1943 UNiTED STATES PATENT OFFICESUBMERSIBLE STRUCTURE Thomas G. Myers, Los Angeles, Calif., assignor toU. S. Electrical Motors, Inc., Los Angeles, Calif., a corporation ofCalifornia Application November 8, 1937, Serial No. 173,434

4 Claims.

This invention relates to submersible structures, such as submersibleelectric motors adapted to be lowered ina well for driving a pumpdirectly connected to the motor.

Usually the material pumped from the well is of such character as to beharmful to the motor should it enter into the motor casing. For exeample, when water is pumped, it should be kept away from the windingsand contacting parts,

so as not to cause electrical circuits to be im` properly established,that would disable the motor. Also, such liquids usually carry grit,sand or other foreign matter that would quickly ruin the bearings insideof the motor. Accordingly it is of considerable importance to segregatethe casing interior as completely as possible from the liquid in whichit is submerged.

It is one of the objects of this invention to make it possible in asimple and effective manner to ensure against entry of the externalliquid to the operating parts of the motor.

It has been proposed in the past to provide rotary seals of Variouskinds to effect this result, the seals being disposed around the shaftthat necessarily must extend out of the motor casing. However, sinceYthe motor casing is subjected to varying liquid pressure, dependent uponthe depth at which it is submerged, these ordinary seals have been foundquite inadequate. Itis another object of this invention to provide adouble seal effect to ensure to'a greater degree against failure of theseal.

It is another object of this invention to utilize the rotating contactsurface type of seal to supplement the mercury seal. Y Y It is stillanother object of this invention to provide a combination liquid seal,such as mercury, and a seal formed by contact between a pair ofrelatively rotatable members, the mercury overlapping the region ofcontact.

It is still another robject of this invention to improve in general,seals embodying such relatively rotatable members.

This invention possesses many other advantages, and has other objectswhich may be made more easily apparent from a consideration of severalembodiments of theinvention. For this purpose there are showna few formsin the drawings accompanying and forming part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatthis detailed descriptionis not to be taken in a limiting sense, sincethe scope of the invention is best dened bythe appended claims.

Referring to the drawings:

Figure 1 is a View, mainly in longitudinalsecf tion, of a structureembodying the invention, shown as submerged in a well; Y Y

Fig. 2 is an enlarged fragmentary sectional view of the structure shownin Fig. 1, and particularly showing the construction of the seal for thesubmersible structure; j

Figs. 3, 4 and 7 are views similar to Fig. 2, but illustrating furthermodifications of the seal;

Fig. 5` is a fragmentary sectional View of the lower portion of. asubmersible structure in which the rotating shaft extends downwardlyfrom the casing;

Fig. 6 is aV fragmentary longitudinal Sectional View illustrating amodication of the structure shown in Fig. 5;

Fig. 8` is a'fragmentary sectional View still further enlarged,illustrating the configuration of the sealing surfaces utilized inconnection with some of the modifications shown in the preced inggures;`

Figs. 9 and 1'0` are diagrammatic views illustrating the manner in whichthe sealing surface of Fig. 8 may be constructed.y in order to insure amore perfect seal; y

Fig. 11 is an elevation, partly in section, of a slightly modified formof the structure disclosed inFg. 1: .1,

Fig. 12 is a fragmentary sectional view, of another modication of thestructure shown in- Fig. l; and

Fig'. 13 is a sectional View on an enlarged scale of the pressureregulating valve used with ythe structure of Fig. 12.

The general character of thefsubmersible structure is illustrated tobest advantage in Fig. 1. In this figure there is shown a well casing I.Within the wellY there is shown thesubm'ersible electrical motor 2,which provides at its upperv extremity a driving shaft 3 adapted tobeconnected, for example, to a pump, not shown, for pumping liquid fromthe well. The electrical motor 2 is shown as submergedwithin the liquidd, which in most instances is water.

The electrical motor 2 isV most conveniently of the induction motorsquirrel cage type, having primary orV stator windings 5. These windingsare adapted to be connected, as by: theI aid of cable E, to a suitablesource of electrical power at the top of the well.

Since the liquid 4 carries'foreign particlesfor dirt, the .bearingssupporting-shaft; 3 must be guarded against entry of this liquid.Furthermore, the windings of the motor 2 must also be kept separate fromthis liquid, for otherwise it would quickly disable the motor.

In order to secure these results, a casing structure is provided whichis so arranged that the liquid 4 is excluded from the parts that need tobe protected, for all conditions of operation as regards well pressure,level of the liquid, etc. In this instance, this casing structure isshown as formed by a cylindrical body 'I within which the motor statorlaminations may be supported. Securely attached to the lower end of thebody '1, as by welding, there is an end collar 8. To this in turn isfastened a bearing supporting housing 9. For example, the bearinghousing support 9 may be attached to the collar 8 as by a series ofthreaded studs I0. In this instance the housing 9 provides a stationarycollar II for supporting the outer race of a ball thrust bearingstructure I2. The inner race of this structure I2 is shown as directlysupported upon the shaft 3. Upon this shaft 3 are attached the rotorlaminations, as is well understood. Since the body 'I may be made fromstandard pipe, it is a simple matter t provide the correct length of thebody required for the rating of the particular motor involved. I

At the upper end of the body 'I there is located a collar I3 permanentlysecured, as by welding, to the top of the body 'I. Similarly attached tothe collar I3 is an upper bearing housing member I4. The manner ofattaching this upper housing member I4 to the collar I3 may be by studs,such as I0, threading into tapped apertures in the top of the collar I3.

The housing I4 provides an axial, inwardly extending boss I5. This bossserves as an appropriate support for the outer race of a radial ballbearing structure I6. The inner race of this ball bearing structure maybe directly supported upon the shaft 3.

The shaft 3 extends upwardly through the boss I5 for direct connectionto a pump.v It is apparent that precautions must be taken to prevententry of the liquid 4 around the rotating shaft 3 where it extends fromthe casing structure. The manner in Whi-chthis is accomplished will beshortly described.

The cable 6 extends through a coupling member I'I in fluid tightconnection with the top of the housing I4, leading the connections fromthe winding 5 upwardly out of the casing structure.

It is preferred to have an inert, lubricating liquid filling within thecasing structure. For this purpose lubricating oil is convenient,although other liquids that may be suitable could be used. This liquidlling is indicated by reference character I8 below the thrust bearingstructure I2. The casing structure may be replenished with liquid, asrequired. For example, a supply pipe I9 can be connected tothe top ofthe bearing housing I4, as bythe aid of the pipe connection 20. Thispipe I9 may lead to the top of the Well for appropriate connection to asource of the liquid under suitable pressure.

It is advantageous that the liquid pressure inside of the casingstructure be closely controlled.

is always considerably below the lower bearing structure I2. Since boththe liquid and the water are substantially incompressible, this level 22is maintained substantially constant, irrespective of the depth to whichthe submersible motor is lowered.

Should it ever be desired to change the liquid filling while the motoris submerged, it is possible to urge liquid downwardly under pressurethrough pipe I9. The new liquid coming in will express the old liquidoutwardly through the aperture 2I, and the casing will be maintainedfull with the freshly supplied liquid.

It may be desirable to have the pressure within the motor casingdifferent from that existing outside of it. Thus in the form ofstructure shown in Fig. 11, a casing 280 is provided which may besimilar to casing of Fig. 1 and supports the motor stator and rotor inthe same way. The motor shaft 28| extends upwardly out of the casing forconnection to a pump as before, and is provided with any appropriateseal, such as disclosed herein, to prevent entry of well liquid to thecasing. The casing is closed at its lower end with a domed head 282, andno provision is made to permit entry of well liquid to balance theinternal and external pressures. Liquid for lling the casing is suppliedthrough a pipe 223 extending from the top of the well, and a return pipe284 extends from the bottom of the casing to the top of the well. Bymeans of these pipes and suitable apparatus at the top of the well,liquid may be supplied to the casing or circulated through it, thepressure being kept at a suitable value.

In Figure l2 a form of structure is disclosed in which means areprovided to maintain the pressure within the casing at a predeterminedamount above that prevailing outside 0f it. This is often desirable,since any leakage that occurs will then be outward from the casing,insuring againstV entry of the well fluid. The casing 290 in this formis again similar t0 the structure of Fig. 1, appropriate sealing meansbeing provided where the shaft 29| Vpasses through the top of thecasing. The lower end of the casing is provided with a head 292 whichexcludes the well fluid.

The liquid 293 inthe casing is supplied under pressure and in regulatedamount through a conduit 294, having its upper end at the top of thewell. The automatic pressure control is effected by a pressure regulator295, interposed in this conduit, and which is shown in greater detail inFig. 13.

Frame 296 of regulator 295 has an inlet 291 and an outlet 298, onopposite sides of a dividing wall 299. This wall supports a member 300,as by screw threads, forming a valve seat 30I. A valve closure 302cooperates with the valve seat and is urged to closing position, as bythe spring 303 held in cage 304. There are, however, additional opposingforces acting to open the valve, which forces act to insure the pressureof well liquid outside of casing 290atapproximately the level of thecasing, plus an added pressure, exists inside the motor casing 290.

'Ihus closure 302 is fastened to a stem 305 extending through member309. At its upper end, stem 305 is fastened to a guide 303 joined to adiaphragm`301. This diaphragm can be metal or leather or the like, andcan be held in place by a cover member 308 Vapertured as at 309 .topermit thewell pressure to be exerted on the upper surface of thediaphragm. "supplementing this external pressure of the well liquid. is;the` pressure of a compression spring 3m. l spring has a guide or shoe3H resting on the diaphragm 36T, and its upper end rests' againstlasupport 3I2. The pressure of the spring isadjus'table by the aid of aset screw 3|3 inY cover 308,k to pro-vide an adjustment of the totalpressure on diaphragm 3D1. The lower surface of diaphragm 331 is exposedto the opposing pressure in casing 293 Via conduit 234.

It is apparent that the diaphragm 301 urges the valve to open when thepressure acting on its upper surface exceeds the pressure of the liquidin the casing 230, acting on the lower side of the diaphragm 30T. Thusas the casing 290 is lowered into the well, the liquid 233 is forcedunder pressure into the casing until closure 332 is urged to closingposition against its seat. If the pressure in casing 290 is reduced toan undesirable value, the closure 332 thereduction in pressure on thelower side oi the diaphragm, and additional lubricant is supplied untilthe pressure becomes enough greater than the well pressure to maintainthe casing 290 clear of the entry of any foreignmatter.

The liquid 293 expands and contracts in accordance with temperaturevariations. To permit this, without the attainment of excessivepressures, a Sylphon 3M is provided, in communication with casing 293,as by nipple 3l5. The liquid therefore, is permitted to expand andcontract and correspondingly expand and contract Sylphon Sill. SpringSis acts on the Sylphon, tending to compress it, and rests on astationary support 3H located in a cover BIS. By appropriate design ofthe spring SIE and Sylphon 3M, the arrangement is such that variation inthe volume of the oil has no material eect upon the automatic pressureregulation.

The shaft 3, shown most clearly in Fig. 2, passes upwardly through aclearance aperture 24 located in the top flange of the tubular casingextension 23. This tubular extension 23 is joined to the casingstructure as by being threaded into the top of the bearing housingstructure I4. The water from the well, of course, may enter around theshaft 3 through the clearance aperture 24. However, it is prevented fromentering through the boss I5, by the provision of a sealing structurenow to be described. This sealing structure involves in general theprovision of a pair of annular sealing surfaces arranged to be placed incontact with each other, one of which is nonvrotary and supported by thesubmersible casing,

and the other rotary and supported by the shaft 3. This surface seal isenhanced by the aid of a supplemental liquid seal, such as mercury orcarbon tetrachloride, thus providing a double sealing effect.

For example, in the form shown in Figs. 1 and 2, the shaft 3 carries acup 25. This cup is urged against a shoulder 2S on shaft 3, as by theaid of the nut 2l threaded on the shaft 3 and maintaining the cup 25 inliquid tight connection with the shaft 3. The upper edge of cup 25 isshown as being in contact with the lower edge of flange 28 which isformed upon a non-rotary collar 23. This collar 23 is supported by thetubular member 23 in such a way as to permit vertical movement whilemaintaining the annular surface around shaft 3 separate from theinterior of the tubular member 23. For example, this may be accomplishedby the aid of a metal bellows 33. This metal bellows is joined in fluidtight manner is depressed, because of at .its top to the shortdependingflange 3i ex- 753 tending from the. top of the. tubular housing 23. Thelower end of the metal bellows 30 is similarly permanently secured tothe flange 32shown.

as integral with the collar 29. A compression spring 33 is in Contactatv its upper end. with the lower surface of the top flange of tubularmember 23. The lower end of compression spring 33 rests upon the collar29 to urge the collar and the ange 28 downwardly against the outer edgeof the cup 25.

The liquid 4 from the well may enterinto the space Withinthe bellows 30and into the cup 25. It would, however, be prevented from entry into thecasing structure bythe annular seal provided: between the relativelyrotating parts 25 and, 28. In some instances this seal might besuicient; however, in the present instance this sealing effect isenhanced or fortied by the use of a heavy liquid filling 34 within thecup 25 and overlapping the surface of contact between members 25 23 maybe of the form illustrated in Fig. 8. For

example, this area of Contact may take the form of a rather narrowannular band 35 (Fig. 8) provided by forming one of the two relativelyrotating parts with an annular rib or projection 36. By providing anarrow annulus of this character, unevenness of the surfaces of contactWould not materially affect the quality of the seal, especially afterthe mechanism has been in operation for a period and has worn in.

In Fig. 2 the space between cup 25 and flange 28 may be in communicationwith an outlet 3l for filling this space with the appropriate heavyliquid as required. This filling aperture may be closed by anappropriate plug as indicated.

The characteristics of the seal shown in Fig. 2 may be summarized asfollows: the use of a rotary and non-rotary member having annularsealing surfaces in contact; the use of a Syl'phon or metal bellows tomake it possible to urge one surface against the other whilemaintainingsegregation of liquid from one side to the other of the seal; the use ofthe pressure inside the chamber containing the inert liquid to create aforce holding the sealing surfaces together; and the use of asupplemental heavy liquid overlapping the area of contact to augmentand. supplement the sealing effect of the relatively rotatable annularsurfaces. In the form shown in Fig. 2 the heavy liquid or mercury 34 isshown as disposed within a rotary cup 25.' In this way, some centrifugalaction is imparted to the liquid 34, causing it to pack rather tightlyagainst the sealing members.

By appropriate choice of areas of the rotary and non-rotary sealingmembers, which are exposed to the liquid pressures existing within andwithout the casing, it is possible to cause a preponderance of pressureurging the members together to sealing position; and if desired, thispressure urging the members together may be increased by increasing thepressure within the casing over that existing outside the casing.

The use of the Sylphon or flexible member between the stationary memberand the contact surface, prevents vibration in this part from beingtransmitted to the junction of the sealing surface which would tend tobreak the seal. This flexible member also allows the sealing surfaces tofollow inaccuracies in the contacting members and misalignment of theshaft 3 and other inaccuracy tending to open the sealing surface.However, it is possible to use several other modications as far as thedisposal of the liquid seal is concerned.

Another form of the invention is illustrated in Fig. 3. In this case theshaft |00, which extends upwardly out of the casing ||J|, carries therotary sealing member |02. This sealing member |02 is supported on thebottom of the metal bellows |03, the top of which is supported on thecollar |04 fastened to the shaft |00. The sealing surface of the member,|02 is in contact with the annular upper edge of a non-rotary cup |05.This cup in this instance is supported on the shoulder |66 formed aroundthe top of the bearing boss I5. It is held in fluid tight manner againstthe shoulder |06 by the bottom edge of the tubular housing extension|01. The supplemental liquid seal |03 is disposed in the annular spaceformed between members |05 and |62 on the one hand, and the innerannular flange |09 on the other hand. As before, the heavy liquid seal|08, which may be mercury, overlapsthe area of Contact between therotary and non-rotary sealing members.

In this instance the top of the mercury sea-l |08 is in contact with theliquid filling in the casing The water in the well enters into theannular space between the extension |01 and the metal bellows |03.

In the form of the invention illustrated in Fig. 4, a stationary cup |36is provided, supported on the shoulder |40 of the casing |4|. It is heldagainst the shoulder |40, as by the aid of the tubular extension |42,threading down on to the annular ange |43 disposed around the exteriorportion of the cup |39.

This cup |39 is provided with an inner annular member |44 andintermediate annular member |45 and exterior annular member |46. Theintermediate annular member |45 in this instance lprovides the sealingsurface cooperating with the rotative member |41. This rotative member|41 is supported on the bottom of `the metal bellows |48. The upper endof the bellows |46 is fastened in iiuid tight manner to a collar |49vfastened in any appropriate manner to the shaft |50. Com-I pressionspring urges the rotary member |41 into contact with the intermediateflange |45.

In this case, two liquid seals are provided. One seal |52 is disposedwithin the intermediate annular flange |45 and has its surface incontact with the oil filling the casing |4|. The other liquid seal |53extends around the intermediate flange |45. Both liquid seals |52 and|53 may, as before, be formed of mercury-and overlap the relativelymovable contacting and sealing surfaces. The surface of liquid seal |53is in contact with the liquid 4 which enters into the extension |42. Y Y

It is not essential, in order to utilize the seals corresponding to thisinvention in a casing, that the shaft Vextend upwardly out of thecasing. In the forms of the invention illustrated in Figs. 5 and 6. theshafts are shown as extending downwardly from the fluid tight casing.

Thus in the form of Fig. 5 the motor 2 is shown as having a shaft 16|extending downwardly through the bottom flange V|62 of the bearinghousing member |63. A downwardly extending tubular extension |64 isprovided surrounding the shaft |6I. Supported on the shoulder |65surrounding shaft |6|, is an annular non-rotative sealing member |66. Itis held in place by the upper end surface of the threaded end of tubularextension |64.

Contacting with the lower edge of the nonrotative member |61 is theupper edge of a rotative cup member |61. This cup member is supported bythe metal bellows |68, the lower end of which is supported on the collar|69 fastened to a shaft, |6 Compression spring |10 urges the two sealingmembers |66 and |61 together.

In this case also a heavy liquid seal |1|, such as mercury, overlaps theareas of contact between the sealing members. It is disposed inside ofthe cup |61 and fills the intervening space between the metallic bellows|68 and the shaft In order to make it possible to replenish the liquidseal |1|, a feeding tube |12 is shown as supportd in the wall of thehousing |63 and leading downwardly into the space formed between thestationary member |66 and the shaft |6|. This tube may be closed fluidtight, as by the aid of a taper threaded plug |13.

In the form of the invention illustrated in Fig. 6, the casing |14 isshown as having a tubular extension |15 fastened to the bottom thereof.Through this extension extends the shaft |16. This shaft |16 passesthrough the clearance aperture |11 formed in the bottom of member |15.An inner annular flange |18 forms a non-rotary cup. In this instance thecup is formed with an intermediate flange |08, the upper edge of whichis intended to be in sealing contact with the rotary sealing member |89carried on a Sylphon or metal bellows fastened at its upper end to therotary collar |8| attached to shaft |16. In the present instance thecollar |3| is shown as urged against the shoulder |82 on shaft |16, asby the aid of a sleeve |83 urged upilv'ardly, as by the nuts |84threaded to the shaft Thus there are two liquid seals, one inside andone outside of the intermediate annular flange |88; an inner liquid seal|90 in contact with the exterior liquir of the well, and an exteriorliquid seal |9| in contact with the lling of the casing |14. Both liquidseals, of course, as before, overlap the areas of contact.

It may be desirable in some instances to provide a structure that willmore fully insure proper alignment between the sealing surfaces.

One such construction is illustrated in Fig. 1. In this form a shaft 20|extends upwardly out of a fluid tight casing 200. A non-rotary annularmember 2|4 is fastened within a, recess 203 in the top wall of thecasing 206, as by the aid of the screws 204. This annular member 2|4 isformed as the outer edge of an annular cup having an inner ange 2|5. Therotary sealing member 2 3 is urged downwardly into sealing contact withmember 2|4, as by the aid of the compression spring 206. The. metalbellows 201, as before, serves to segregate the spaces on either side ofthe sealing members. This metal bellows is fas-` tened at its bottom tothe rotary member 2|3 and at the top to the cap 208 fastened to theshaft 20|.

Under certain load conditions, transverse flexure of shaft 20| ispossible. This flexure may disturb accuracy of contact between therotary and non-rotary members 2|3 and 214. In order to guard againstsuch an occurrence, a telescoping guide is provided, such as a tubularextension 2|6 attached to the rotary member 2|3 and guided on theexterior surface of the non-rotary member 2|4. This telescopic member2|6 is in sliding relation with the member 2|4 and provides asupplemental seal between the members 2|3 and 2|4. A heavy liquid seal2|`| is disposed within the ange 2I4 and overlaps the sealing surfaces.It is apparent that the surface of the liquid seal is in contact withthe lling of casing 260.

It is further to be noted that even if shaft 20| flexes transversely ofits axis, this lexure is permitted by the flexibility of the metalbellows 201, without in any way disturbing the proper alignment betweenthe sealing surfaces. Furthermore, the machining of the partstelescoping together facilitates the assembly of the contacting sealsuifaces. It also makes possible checking of the accuracy thereof priorto installation of the motor casing, and eliminates the necessity ofextremely accurate machining of other parts.

In general, it is advisable to insure as perfect smoothness of thecontacting sealing surfaces as practicable; otherwise, it may benecessary to wear in the sealing surfaces. Such wearing in may requirethe necessity of dragging off minute pieces of metal, which mayadversely affect the seal.

In order to obviate this, the sealing surfaces are preferably compressedsmooth, as by the aid of a die or by the aid of a hard metal roll. Inthis connection attention is invited to Figs. 9 and l0. In Fig. 9 thedie 264, made from hard metal and carefully polished in its annularrecess 265, is used for forming the sealing member 266. By providingsufficient pressure, the smoothness of the sealing surface thus providedmay be very materially improved.

Alternately, as shown in Fig. 10, the sealing surface 261 may be rolledsmooth, as by the hard metal roller 268.

The character of the contacting surfaces in connection with all of theseals illustrated in these various modifications may be given someconsideration. In some instances one of the two relatively rotarymembers may be made from a metal which forms a mercury amalgam, such ascopper. The liquid seal being in the form of a body of mercury, reactswith the metal and forms an amalgam that acts somewhat as an oil film.The effect of providing the amalgam at the contacting surfaces is tosmooth out any inequalities thereof.

Also in some instances the character of the ma;

terials in contact between the rotary and nonrotary sealing members maybe purposely chosen for durability and smoothness, and capability ofretaining the required high degree of smoothness for extended periods ofoperation. As examples of the character of these contacting surfaces,may be mentioned bronze or steel, hardened as by car- `burizing. 'Ihesteel may be hardened, in addiof these surfaces discussed applies to allof the forms of the invention illustrated in the drawings.

From a consideration of the description of the various forms of theinvention, it is seen that they include the contact of liquid withrelatively rotating parts. The liquid may be mercury, oil, water, carbontetrachloride, or their equivalents. It has been found that the liquidsin contact may tend to emulsify and to affect the seal deleteriously.Also, such liquids as mercury tend to combine chemically with therelatively rotating sealing surfaces. For example, bronze or steelrotating in mercury may combine to form a black powder.

In order to obviate these occurrences, the various surfaces in contactwith the liquids utilized in the seal may be protected as by a ceramicenamel, or by baked enamel. The enamel reduces the frictional loss,emulsion is retarded, and since the enamel is inert, chemical action isprevented.

Such a construction may be applied to all of the forms heretoforedescribed.

The layers are also indicated specifically in Figs. 2, and 4. In Fig. 2the layers 325, 326 are thus intended to overlap the region of contactbetween the liquids. In Fig. 4 both bodies of the liquid seal |52, |53may be isolated by the layers 32|, 322, and 323, 324.

What is claimed is:

1. In a submersible structure, a casing, a rotary shaft extending fromthe casing, an annular non-rotary cup, having an outer wall and an innerWall, surrounding the shaft, a rotary member having an annular surfacein contact with the outer wall of the cup, a metal bellows carried bythe shaft and supporting said rotary member, and a liquid seal in thecup, overlapping the contacting areas.

2. In a submersible structure, a casing, a rotary shaft extending fromthe casing, a nonrotary annular cup supported by the casing, said cuphaving an inner and an outer annular edge, surrounding the shaft, arotary member having an annular surface in contact with the innerannular edge, and carried by the shaft, and a liquid seal in the cupbetween the inner and outer edges, and overlapping the area of contact.

3. In a submersible structure, a casing, a rotary shaft extending fromthe casing, a non-rotary annular cup surrounding the shaft, said cuphaving an inner and an outer annular edge as well as an intermediateflange forming an intermediate annular edge, a rotary memberhaving anannular surface in contact with the intermediate annular edge andcarried by the shaft, and liquid seals in the cup on respectivelyopposite sides of said intermediate ange and overlapping the area ofcontact.

4. In a submersible structure, a casing, a rotary shaft extendingdownwardly from the casing, a non-rotary annular cup supported below thecasing and having an inner annular ange and an intermediate annularange, a rotary member carried by the shaft and having an annular area incontact with the intermediate annular ange, and liquid seals onrespectively opposite sides of said intermediate flange and overlappingthe area of contact.

THOMAS G. MYERS.

